Penelope Cruz is going to be an aunt! The actress' look-alike younger sister, Monica Cruz, is pregnant with her first child -- thanks to an anonymous sperm donor, she wrote on her blog for Spanish newspaper El Pais.

The Agent Provocateur model and mom-to-be, 35, announced the news in a post titled "My Life's Dream" earlier this month. "I'm going to be a mother!" she wrote in Spanish. "I have managed to fulfill the dream of a lifetime. Because of that, I want to share with all of you this special journey and be able to tell you about all of my experiences during this fascinating time..."

Cruz then went on to say that although she would have preferred to wait for the man of her dreams before having a baby, she couldn't ignore her ticking biological clock. "A 40-year-old woman is very young and she feels very young, but the maternity thing goes another way. It is measured with another clock that unfortunately we do not control," she explained. "I've become very informed on the subject. It turns out that after 37 the possibilities of becoming pregnant decrease at an alarming rate."

Because of that, she opted to take matters into her own hands. And though she initially hid out to avoid having to deal with speculation about the pregnancy, she's ready now to tell all.

"I've decided to talk about it: I have resorted to artificial insemination in order to get pregnant," Cruz wrote. "I also wanted to talk about it because it is an opportunity to show my gratitude to all those anonymous donors that help a lot of women, like me, fulfill their lifetime dream. If with this I can help others that are in doubt, here I am for whatever you may need."

Now that her pregnancy is out in the open, Cruz -- whose sister, Penelope, gave birth to son Leo in January 2011 at the age of 36 (with husband Javier Bardem) -- is following suit. On Friday, Jan. 25, the model debuted her barely-there baby bump while shopping in Madrid, Spain. Wearing jeans, wedged boots, and a black coat with a fur collar, the Spanish-born beauty looked glam and glowing.

Cruz rose to fame in her native Spain in the early 2000s on the TV show Un Paso Adelante. She also doubled for her pregnant sister during filming for Pirates of the Caribbean: On Stranger Tides in 2011.